In my case it was - in the first instance -
not an Audi at all, but a Lexus LS, when a work colleague picked me up at O'Hare Airport in late '90s in his immaculate LS400. I couldn't believe the quality, quietness and comfort of it, which piqued my interest in "luxobarges" (although I hate that term!).
Three or four years later, that interest morphed from Lexus to Audi (predictably...) when I saw Ronin in 2002, and another six years later - after looking at loads and loads of D2s - I ended up with Herman, and have never regretted that choice.
However, I still have a soft spot for the big Lexus though, and this new Jay Emm review:
https://youtu.be/tLxpYEVe8uA
of the 600Lh brought back all of the charms of this lovely limo - as well as him giving a little nod to the S8 over the Merc and BMW